The present invention relates to an automatic punching machine, particularly one suitable for performing punching of a metal sheet in a programmed and programmable manner according to a predetermined number of different punching shapes.
The punching machine of this invention is of the type comprising a punching head provided with a plurality of punch/die pairs for effecting the desired punching of a metal sheet, and a numerically controlled programmable manipulator, equipped with gripping means for the said metal sheet, for displacing it over a horizontal plane passing between the said punches and their associated dies.
In known punching machines of the said type there exists a single, well determined and unchangeable operative position, into which each punch/die pair is carried by appropriate automatic means and retained for the time necessary for the execution of all the punchings of the same predetermined shape envisaged in a metal sheet.
In operation of such a known punching machine, whilst a first punch/die pair is maintained in the said operative position the manipulator causes the displacement of the metal sheet in such a way that the said pair performs the predetermined number of identical punchings in a corresponding number of predetermined and different positions in the said metal sheet. Once this first series of punchings has been completed the punch/die pair first considered is replaced with another pair of different shape to effect a second series of punchings on the same metal sheet.
This mode of operation, which is tied to the structural and functional characteristics of the known punching machine and, above all, to the fundamental characteristic consisting in a single and unchangeable operative position, involves dead times which until now were inevitable, for the substitution of the punch/die pair in the operative position, as well as a not inconsiderable consumption of time tied to the movements which the manipulator must perform in order to displace a metal sheet during the operation of successive punch/die pairs.
This disadvantage leads to a reduced capacity of the known punching machines.
The main object of this invention is, consequently, that of making available an automatic punching machine having structural and functional characteristics such as to eliminate the said dead times and to reduce substantially the consumption of time involved in the displacement of a metal sheet by the manipulator.